Extremely interesting, I'm intrigued at the idea of preserving fragmentary historical accounts by weaving them into a semi-fictional narrative (which I suppose is something that ancient historians themselves frequently did). > Maximinus and I looked at each other, and I recall that I shrugged my shoulders unhelpfully. Is the author taking playful liberties with the metafictional "translation" here, or is the gesture…
The only thing I saw that might be about it is in Quintillian, which doesn't interpret it exactly as we would - seeing it more as a servile gesture:
"humerorum raro decens adleuatio atque contractio est; breviatur enim cervix et gestum quendam humilem atque servilem et quasi fraudulentum facit, cum se in habitum adulationis, admirationis, metus tingunt." ( http://www.perseus.tufts.edu/hopper/text?doc=urn:cts:latinLi... )
"It is, as a rule, unbecoming to raise or contract the shoulders. For it shortens the neck and produces a mean and servile gesture, which is even suggestive of dishonesty when men assume an attitude of flattery, admiration or fear." ( https://penelope.uchicago.edu/Thayer/E/Roman/Texts/Quintilia... )
It's not completely clear to me from a cursory glance if he isn't talking about posture rather than the gesture though shrugs